Fitting for electric lamps.



N0. 857,928. w PATENTED JUNE 25, 1907.

- J. DUGDILL.

FITTING FOR ELECTRIC LAMPS.

APPLICATION FILED NOV. 3, 1906.

PATENTED JUNE 25, 1907.

J.. DUGDILL. FITTING FOR ELECTRIC LAMPS.

APPLICATION FILED NOV. 3, 1906.

2 SHEETS-SHEET Z.

NITED PATENT orsion.

FITTING FOR, ELECTRIC LAMPS.

Specification of Letters Patent.

. Patented. June 25. 1907.

. -Applicatiou'filed November aisoafseraliio. 341,850. I

Teal; whom it may concern.- m Be it known that I, JOHN DUGDIYLL, a subject of Great Britain, residing at 305 Old .ham road, Failsworth, near Manchester, in

the county'of Lancaster, England, electrical engineer, have invented new and useful Improvements in Fittings for Electric Lamps,-

of which the following is a specification.

My invention relates to electric fittings of the'type having joints whereby the lamp can be set at varying angles, and means for rotating thelamp around an axis. In such fittingsgl employ a novel type of knuckle j oint which will give the maximum amount of friction between the forks of the joint'and .a minimum amount of friction on the axis thereof, so 'that'jthe joint will not beliable. to wear slack, and also novel means whereby the lamp may be rotated.

The accompanying drawings show various types of electric. fittings provided with my improved rotatable means and oint.

Figure 1 shows in elevation myiinvention applied to a very convenient type of electric fitting. Fig. 2is afplan view of part of Fig.--.T.' Fig. 2 is a modification of the rota table means. "Fig. 3 is a view, partly insection, of a detailpart showing the improved. knuckle joint.

on "an enlarged scale. Fig. 4 shows inelevae tion .a modification of electric fitting having Fig. 3 is a portion of Fig. 3

the rotatable joint to which the knuckle joint may be applied; Fig. 5is an underside plan view of Fig. 4 on "theiline A Bf Fig.

6 is .a' further modification showing the rotatable means and knuckle joint.

In constructing the electric fitting to tom the improved knuckle joint I slit the end of a .tube or part a and open. it out .to provide a fork it. Another tube or part g is similarly dealt 'with to produce a forkni and the two forked ends'ucare placed one within the. other and a hole pierced through them, A tubular distancepiece 'or sleeve w is dis-j posed between the bored-arms and a bolt 9 inserted through the arms and the sleeve,

and .by means of a nut qgthe jointiis completed. The holes through the sleeves w and the inner arms '0 are larger in: diameter than the bolt g to avoid friction between these parts and the bolt, and the margins of'all the holes in the forked ends are dished inward. inprder'better to center each within the other, and to provide a conical friction sur :face in addition to the plane friction surface between the two forks as indicated. in the enlarged view Fig. 3. The dishing of the holesis'not essential but is preferable. In this manner'l obtain a good constant frictiori joint without any tendency for the joint to work slack,.and further-provide a free :open way for the conductorsto reduce chafing; This novel construction of. knuckle joint gives a maximum amount of friction between the forks of the j oint-and a minimum of friction on the axis of the joint, besides leaving am )le space for the passage of the wires inclosed in the tubes of the fitting.

as shown in a'detachable electric lamp illus trated in Figs. lto 3 thetube or arm a, of cohvenientlength, is connected to a disk or part b, which I will hereafter term the tube carrier, by a j ointbymeans of which the tube or arm is capable of being rotated on its aXis in either direction as shown by the arrow Fig. 1. The joint is formed by means of a flange or collar 0 on the tube, rotatable in a bearing (1 attached to the tube carrier 1). The conducting wires e are led through the tube carrier 12, and to prevent the wires from being injured by persistent rotation in any onel-direction I may provide means to limit the eXtent of rotation of the tube a to a complete revolution in either direction, although .these'means may be dispensed with if dea projection or Stud 0 on the flange c of the rotatable tube (1 adapted to come into con tact with 'afinger f pivoted to'the tube carrier b, This finger may have sufficient freedom ofgmovement' to enable the tube to be .either direction of rotation.

'mentw-ill be better comprehended from an inspection of Fig. 2 which is an underside carried by .the collar 0 on the tube a being shown in dotted lines. Fig. 2? shows how the same effect may be obtained .by attaching the tube or arm a to ascrewed head (1 either way in the internally screwed tube carrier 6. I do not claim it.to be novel per so in electric fittings to provide means for rotating thelamp around a central axis and to set the lamr'i'at-varying angles. The lower end To provide the rotatable part of the fitting sired.v Such means conveniently consist of "plan view of the tube carrier 12, the stud a" of the tube or arm a is attached by the im rotated on its-[axis a complete 360 degrees in The arrangewhich can be rotated a complete revolution proved knuckle joint to the lamp holder 9 which lamp holder, including the attached member g" of the knuckle joint, is much shorter in length than the tube a. The

lamp h, shovvndotted in Fig. 1 Inay not only be rotated about the axis of the tube a but may also be fixed at varying angles-by means of the iniproved knuckle jo1nt.-

4 The tube carrier 6 is provided with a plug connector iosuch es is commonly used for I portable lamps so'that it maybeconnected form of cord rip, although other forms o cord gripcould be employed, and is susat once with existing lamp fittings. InFigs. 4 and 5 the tube carrier b-provided with'the rotatable joint'c'is shown as embodying on pended directly r'ronrconducting Wires such connector or other fitting.

, In Fig. othe'tube is shownas provided, in

as e, the Wires e'being secured to the plug. I

addition to the rotatable joint 0, with anadditional knuckle joint h of the improved joint consisting of overlappingouter forks u and inner forks 12 having holes bored therein I 30 dished inward to form conical friction surfaces, a tubular sleeve located between the members ofthe inner fork, a bolt inserted throughthe holes infthe' forks and the sleeve smaller in diameter' than the sleeve and the holesin the inner forks, and a nut on such 'boltsubstantially as described.

In electric fittingsthe improved knuckle In testimony whereof I have; signed inyl name tothis specification twosubscribing witnesses JOHN DUGDILL.

the presence of Witnesses:

} .JQSHUA ENTWISLE, 'ALFRED .YATES. 

